The present invention relates to an ultrasonic endoscope, an end portion of which is inserted in bronchial tubes with optical observation to obtain ultrasonic sectional images of slices thereof.
Conventionally, ultrasonic endoscopes have been utilized. Most of the ultrasonic endoscopes are used for digestive tubes. Such endoscopes are constructed such that a bendable portion is formed at a distal end portion of a flexible insertion tube. The bendable portion is generally formed to bend in arbitrary direction by the operation of the proximal end side thereof. Further, an end side main body, which is provided with an ultrasonic scanning unit and an optical observing unit, is connected to the tip end of the bendable portion.
The optical observing unit is formed with a pair of forward-inclined surfaces, one of which is provided with a treatment instrument projection groove, and the other of which is provided with an observing window and an illuminating window. In the treatment instrument projection groove, a rockable table which is remotely operated to rock for adjusting the projecting direction of the treatment instrument, is provided.
An objective optical system for optical observation is preferably configured to view an inclined area with respect to the forward direction of the insertion tube so that a portion to which the ultrasonic scanning is applied, and the optical axis of the objective optical system is preferably inclined by 45-60 degrees with respect to the forward direction of the insertion portion.
The ultrasonic endoscope as described above cannot be inserted in the bronchial tubes, since its outer diameter is too large. However, it is difficult to reduce the outer diameter of such an insertion tube in view of its mechanical strength/structure.
Further, in the conventional ultrasonic endoscopes, observing characteristics thereof may not be appropriate for observing the bronchial tubes, and the insertion tube may be inserted half-blindly. In such a case, if mucosae of the bronchial tube is strongly rubbed, a patient may have a fit of coughing, and investigation may be disturbed.
Furthermore, one of the purposes to insert the ultrasonic endoscope in a bronchial tube is to execute the centesis using a centesis needle with monitoring the ultrasonic cross sectional images of lymph nodes around the bronchial tubes.
The lymph nodes are located at positions apart from the wall of the bronchial tube by 2 mm at the closest, and 10 through 15 mm for farther ones. When the conventional ultrasonic endoscope is used for the centesis, the lymph nodes relatively far from the wall of the bronchial tube may be out of a range of the ultrasonic scanning, and thus, the position of the lymph nodes cannot be determined accurately.
It is therefore an object of the invention to provide an improved tip end of an ultrasonic endoscope which can be used in bronchial tubes with allowing optical observation thereof.
Another object of the invention is to provide an improved tip end of an ultrasonic endoscope which enables monitoring of the ultrasonic images of lymph nodes even if they are apart from the wall of the bronchial tube and allows the centesis operation to be performed safely.
For the above object, according to an aspect of the invention, there is provided a tip end portion of an ultrasonic endoscope having a flexible insertion tube, a bendable portion being formed at a tip end portion of the insertion tube, the bendable portion being bendable in an arbitrary direction along a predetermined plane, a tip end main body provided with an ultrasonic scanning unit and an observation unit being connected to a tip end of the bendable portion, the tip end main body having a tip end side portion and a rear end side portion. The tip end side portion of the main body is provided with a convex type ultrasonic probe for performing sector scanning with ultrasonic waves, and the rear end side portion of the main body being provided with: an instrument outlet allowing a treatment instrument to protrude toward a forward-inclined direction, the outlet being located at a central portion on a cross section of the rear end side portion; an observation window for viewing forward-inclined area which is directed to a forward side with respect to a scanning direction of the ultrasonic probe, the observation window being located, on one side of the instrument outlet; and an illumination window for emitting and illuminating an area to be observed through the observation window, on the other side of the instrument outlet.
With the above structure, the tip end of the ultrasonic endoscope can be made sufficiently slim, and accordingly, can be inserted in the bronchial tubes easily. Further, the forward portion of the inserted tip end can be optically observed, which also enables a smooth movement inside the bronchial tube.
Optionally, a protruding direction of the treatment instrument may be directed toward a forward side with respect to a scanning direction of said ultrasonic probe.
Further optionally, an axis of observation through the observation window may be inclined at an angle within 5xc2x0 through 45xc2x0 with respect to a forward direction of the insertion portion.
Still optionally, the center of the scanning direction of the ultrasonic probe may be formed to incline by 75xc2x0 through 90xc2x0 with respect to the forward direction of the insertion tube.
Furthermore, the surface of the ultrasonic probe may be a spheric convex surface, a radius of curvature of which being within a range of 5 through 15 mm.
Further optionally, the tip end of the endoscope may be provided with a pair of signal transmitting cables for transmitting/receiving electrical signals to/from the ultrasonic scanning unit. The cables may extend along the insertion tube and be aligned side-by-side.
According to another aspect of the invention, there is provided a tip end portion of an ultrasonic endoscope having a flexible insertion tube, a tip end main body provided with an ultrasonic scanning unit and an observation unit being connected to a tip end of the insertion tube, the tip end main body having a tip end side portion and a rear end side portion. The tip end side portion of the main body is provided with a convex type ultrasonic probe for performing sector scanning with ultrasonic waves, and the rear end side portion of the main body is provided with: an instrument outlet allowing a treatment instrument to protrude toward a forward-inclined direction, a protruding direction of the treatment instrument being directed toward a forward side with respect to a scanning direction by the ultrasonic scanning direction; and an observation window for viewing forward-inclined area which is directed to a forward side with respect to the protruding direction of the treatment instrument.
With this structure, the ultrasonic probe can be inserted with monitoring the optical image of the forward portion thereof, and the centesis operation can be done safely since the lymph nodes, whether they are apart from or close to the wall of the bronchial tube, may remain within a range of the ultrasonic scanning.
Optionally, the center of the scanning direction of the ultrasonic probe may be formed to incline by 75xc2x0 through 90xc2x0 with respect to the forward direction of the insertion tube.
Further, the surface of the ultrasonic probe may be a spheric convex surface, a radius of curvature of which being within a range of 5 through 15 mm.
Furthermore, an axis of observation through the observation window may be inclined at an angle within 5xc2x0 through 45xc2x0 with respect to a forward direction of the insertion portion.